Current susceptibility to acid regurgitation, any orthodontic appliances, restorations, bridgework or dentures that in the opinion of the investigator would interfere with the study outcomes, recurrent or regular aphthous ulcers, severe gingivitis, carious lesions and periodontal disease,signs of severe dental erosion, any condition or medication which in the opinion of the investigator is currently causing xerostomia, and individuals who require antibiotic prophylaxis for dental procedures